Lunyu II. 9. (25)

The quiet receptivity of the disciple Hûi.
The Master said, "I have talked with Hûi for a whole day, and he has not made any objection to anything I said;– as if he were stupid. He has retired, and I have examined his conduct when away from me, and found him able to illustrate my teachings. Hûi! – He is not stupid."

Legge II.9.

The Master asked, 'I can speak to Hui all day without his disagreeing with me in any way. Thus he would seem to be stupid. However, when I take a closer look at what he does in private after he has withdrawn from my presence, I discover that it does, in fact, throw light on what I said. Hui is not stupid after all.'